1. Field of Invention
The present invention relates generally to a scale. More particularly, the present invention relates to a portable scale having an adjusting unit that is not disengaged from a tubular housing even though a user arbitrarily rotates the adjusting unit or set the portable scale to zero.
2. Description of Related Art
A related reference disclosing a portable scale can be referred to U.S. Pat. No. 6,246,017 to the same inventor, issued on Jun. 12, 2001. The portable scale includes a spring received in a tubular or longitudinal housing having a graduation or a length indicia beside a slot of the housing. The spring has one end supported on a cap threading with an inner thread at the bottom of the housing and the other end connected to a pressing element secured to a carrying unit extended through the spring and outward the housing. An object to be weighed can be put on a hook of the carrying unit and then the spring is compressed in proportion to the weight of the hooked object. An indicator can be moved in concert with the pressing element for aligning the graduation and for indicating the weight of the object. The portable scale can be set to zero by rotating the cap and the cap can be moved in the housing and in the direction where the spring can be compressed. However, when the cap is rotated, finger flesh of a user may be clipped by the gap between the peripheral lip of the cap and the bottom of the housing, or even the cap may be dropped from the housing.